Last week I had a high compression cylinder head insert installed on my 250 (S3 insert). Compared it with a standard 250 of the same year (at the dealer's) and it feels much stronger and runs cleaner. So very happy with the result. The high compression is noticeable when starting, but it still starts with the first kick warm, three when cold. 

Strange thing is that the idle went up. Stalling it now is almost impossible, but clutch control needs some adaption.
Any thoughts how idle can increase by a high compression insert?

You are completely changing one part of the combustion equation - something is bound to be affected, in this case the lower end of the "carburetion".  Presumably the ECU needs to be told that the compression has changed?

2 hours ago, 2stroke4stroke said:

You are completely changing one part of the combustion equation - something is bound to be affected, in this case the lower end of the "carburetion".  Presumably the ECU needs to be told that the compression has changed?

According to the dealer remapping of the ECU wasn't required. It does run really great with the high compression insert. 
BTW: the higher idle doesn't bother me at all. 

Hi Tcrhino,

 I believe increase in compression = greater engine efficiency. with the result as u notice increase in idle and fewer flameouts. I was reading an article a few years ago about direct injection in modern automobile engines creating an opportunity to raise compression, with the goal of increasing mileage as well as horsepower. I could be wrong as im no expert. just my opinion.

Maxwell

17 hours ago, maxwell smart said:

Hi Tcrhino,

 I believe increase in compression = greater engine efficiency. with the result as u notice increase in idle and fewer flameouts. I was reading an article a few years ago about direct injection in modern automobile engines creating an opportunity to raise compression, with the goal of increasing mileage as well as horsepower. I could be wrong as im no expert. just my opinion.

Maxwell

To me that makes sense (no expert as well). Same throttle position (closed) and same fuel injection (no other map), but increased idle means more efficient use of the available air/fuel mixture...

tcrhino, what year bike have you fitted this insert to ? 

7 hours ago, jsp said:

tcrhino, what year bike have you fitted this insert to ? 

It was fitted to a 2017 Ice Hell 250

Hi Tcrhino , where did you buy this part please and was it easy to fit ??

3 hours ago, smegyboy said:

Hi Tcrhino , where did you buy this part please and was it easy to fit ??

My dealer -and Vertigo importer for The Netherlands- (Nonstopmotoren.com) sourced the part from S3. Dealer did the installation and I watched how it was done. 

Installation was a bit fiddly because the fan housing is blocking one of the head bolts. Easiest would be to remove the radiator and fan (water is out anyway), but the mechanic managed to do it by only removing the fan. Using new o-rings is important as is applying the correct torque to the head bolts. 
With a bit of patience and the proper tools it's possible to do yourself. 

Wondering if anyone else has tried a high compression insert on a 250 vertigo?

U would think the mixture is changed. Or the particles that find each other, something like that.

Nog engine knocking ? They seem to be sensitive for that ?

Are u maybe by coincidence sometimes in Nunspeet ?